


starlight on your skin

by CharlotteDaBookworm



Series: Regisson AU [1]
Category: Final Fantasy XV
Genre: Age Regression/De-Aging, Alternate Universe - Canon Divergence, Alternate Universe - Soulmates, Angst, BAMF Nyx Ulric, Canon-Typical Violence, Family Bonding, Family Feels, Galahdian Culture (Final Fantasy XV), Gen, Magical Bond, Magical Realism, Nyx Ulric Lives, Nyx Ulric's Self-Esteem, Older!Nyx is Called Astraeus, Other Additional Tags to Be Added, Platonic Relationships, Platonic Soulmates, Post-Traumatic Stress Disorder - PTSD, Post-World of Ruin, Pre-World of Ruin, Royal Bastard AU, Somebody Lives/Not Everyone Dies, Soulmate-Identifying Marks, Time Travel, Time Travel Fix-It, Trauma, Uncontrolled Magic, because I'm not only dumping a post-apocalyptic Nyx back in time I'm also deaging him by 3 decades
Language: English
Status: In-Progress
Published: 2019-05-27
Updated: 2019-09-10
Packaged: 2020-02-09 18:31:05
Rating: Teen And Up Audiences
Warnings: Graphic Depictions Of Violence, Major Character Death
Chapters: 2
Words: 3,153
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/18643705
Author URL: https://archiveofourown.org/users/CharlotteDaBookworm/pseuds/CharlotteDaBookworm
Summary: He’s always known that he’d end up alone. Everyone he loved died, eventually. But he hadn’t expected an apocalypse. He hadn’t expected to be approached by four of the Six with an Offer.And he’d never expected a second chance to save them all.All he has to do is give up all that he is.He’s always been willing to sacrifice himself for those he lovesNyx Ulric dies. 34 years previously, a teenager with darkened stars on his skin and Ulric blue eyes explodes into existence before a boy with those very same eyes who screams as his magic rages under his skin.





	1. Prologue

**Author's Note:**

> I don't own FFXV

***

Nyx had always known that, eventually, he would end up alone.

 

The people he loved died.

 

That was all there was to it – when Nyx loved someone, they died.

 

It had always been that way, even when he was just a small child. The people that he loved – loved enough for bright stars to swirl across his skin in proof – died.

 

 _Always_.

 

And he was always left alone, trying to survive in a world without them. He was always the last man standing.

 

No matter what he did, no matter how he tried and failed, he was always left as the last man standing.

 

~~Standing over the bones and the corpses of the people that he had loved and failed~~

 

So, yeah. He had always known – in the back of his mind, where the little voice that he did his best to ignore whispered, even as he clung closer to those he loved – that one day, he would be completely alone, had always known that each mark that painted itself across his skin just staved that day off a little longer. Was just another heartbreak in the making.

 

He was just throwing stones at a Behemoth, for lack of a better weapon, trying to hold off deaths embrace for a few more seconds, in the futile hope that it would be _enough_ – he was trying to have just a little longer before his skin-sky went dark.

 

Before all of his stars left him.

 

Because they _would_ leave him, in the end. Every single one of them did. It was never their fault, but they left.

 

And Nyx. Nyx was just clutching at straws in a hurricane, holding tight to those he loved before they were finally torn away from him as he’d always known they would be.

 

Mum, Libs, Selena, Crowe, _everyone_ , really – everyone but for Cor; he’d understood, there had always been a silent understanding between them – they’d told him, time after time, that he loved too freely, that he cared too much, that he bound himself too quickly. That he was just setting himself up for a world of hurt. And they weren’t wrong, not really. He’d always known that.

 

There were jokes, too. Both kind and scathing, from people he knew well and people he passed on the street, about the many marks on his skin and _talk about loving a village, ay Ulric? Don’t you know that you should pick quality over quantity_?

 

Nyx laughed them all off, each time, and if he was a little more reckless in the field in the next deployment, well.

 

Who could really complain, anyway? He was just doing his job, was just making sure that his people came back alive, and it wasn’t like it had killed him. He’d survived.

 

He always survived.

 

~~Even when he didn’t want to. Even when others fell because he wasn’t _good enough_. Even when he would give anything to trade places with them because it was all his fault, he should have been faster, should have _seen_ …~~

 

People looked are the marks on his skin – bursts of vibrant colour and flat darkness, swirling around his arms, crossing over his chest and shoulders, spiralling around his neck – and he knew that they thought him naïve, smiling and scoffing in turn.

 

Really, though, he just hadn’t wanted to be alone.

 

~~But Nyx had never gotten what he wanted, had he?~~

 

And then he’s 42 going on 43 and everyone he’s ever cared for – ever _loved_ – is either dead or dying and he can’t even fight what’s killing the last of them; he can’t fight illness, the illness that had somehow managed to avoid him entirely, the illness that was taking the last of his stars from him even after they’d survived this long.

 

Everyone he loves is as good as gone, is fading even now, and his skin is covered in black and rapidly darkening grey – none of the beautiful coronas of colour that had once painted his sky – and he’s alone.

 

He’s _alone_. Just like he’d always known he would be, in the end.

 

He’s alone and it _hurts_ , deep in his chest, a gaping wound that just won’t close because he wasn’t built to be alone – wasn’t built for an empty sky.

 

He doesn’t want to be alone.

 

It’s easy, then, to lean back into the comforting hold of the Stormsender, to smile at the Earthshaker as the ground beneath him rumbles with caution and warnings, to accept the offer that the Tidemother brings to him on the shores of that beach, to meet the eyes of the Frostbringer who stands apart from her siblings but is lending them her support all the same.

 

 _There will be consequences_ , they tell him.

 

 _There are no guarantees in this_ , they tell him.

 

 _Failure or success, this may very well kill you_ , they tell him.

_You will never be as you once were_ , they tell him.

 

 _It must be your choice_ , they tell him.

 

And Nyx…

 

Nyx smiles at these Astrals and it is a broken thing – this small, awkward twist of the lips given by a man who has almost forgotten what it is to smile – and it is paired with dark, tired eyes.

 

Nyx smiles at these Astrals who are trying to fix things – who have looked at a world left to Bahamut’s machinations, to the Draconian’s shadow rule, and decided that _no_.

 

 _No_ , this is not how it should be. This is not how they will let it end.

 

Nyx smiles at them and he is alone, and he has nothing left to live for – he has buried his mother and his sister and his aunt, his father and his brother and his friends, Crowe and Pelna and Luche. He’ll soon bury Libertus and Cor.

 

Nyx smiles at them, an echo of the man that he once was, and he reaches out.

 

It’s easy as breathing, in the end.

 

 _Easier_ , maybe.

 

“Where do I sign?”

 

.

 

..

 

…

 

The world _stutters_.

 

.

 

..

 

…

 

Everything flares white _white **white**_

 

.

 

..

 

…

 

Nyx _screams_ as everything is unmade.

 

As he is unmade.

 

.

 

..

 

…

 

Time winds back

 

.

 

..

 

…

 

 

34 years previously, a teenager with darkened stars on his skin and Ulric blue eyes explodes into existence before a boy with those very same eyes who screams as his magic _rages_ beneath his skin.

 

***

 _A new path is made_.

**Notes for the Chapter:**

> so, this is a prologue for one of my many - as people from tumblr will tell you - regisson time travel au's (no idea what it is about this au that lends itself so well to time travel. it's probably the angst. definitely the angst) and it's also a soulmate au cos why tf not ¯\\_(ツ)_/¯
> 
> anyway, i have a vague plan for this and a whole lot of backstory and meta and hopefully i'll be able to stick with it a while
> 
> i'd hoped to have the first chapter finished before I posted this but the downside to using AO3 drafts is that they only keep for a month and it's post or be deleted so
> 
> thanks for reading, hope you like it, tell me what you think or what you wanna see (i'm always open to asks for any of my verses on my tumblr which is under the same name as this account)


	2. Chapter 1

**Summary for the Chapter:**

> _Brother,_ his magic sings in his chest, and he flinches away from the child staring at him with teary, blurry eyes.

 

* * *

 

Once upon a time, the mere sight of the stars had given him peace.

 

He had learnt their names at his mother’s knee, a toddler clinging to her legs on clear nights as she’d traced the patterns and named each one and told him their stories. Of Galahad, the warrior, the protector, the man who the isles were named for, who had been pressed into the stars after his death by the Astrals.  Of Liberta, the star that guided their people home from the seas, the freedom of Galahd. Of the Sun’s Point, the brightest star in the sky, said to be the once-home of the Astrals.

 

There were so many stars, so many stories, and Nyx had loved them all; sad and happy and everything in between.

 

_The sky doesn’t change_ , he could remember his mother whispering to him one night _, the stars never change, darling boy, no matter where you are in the world, no matter how lost, you can always use them to find the way home._

 

After Galahd’s fall, he’d often turned to the stars – homesick and grieving and _angry_ , so angry, wanting his home so desperately that he ached. And when that ache built up, when the absence of the storms thundering in the sky and the lack of salt on the wind and the bleak coldness of the concrete that surrounded him built up and built up and _built up_ until he felt like he was going to suffocate, he would look to the stars.

 

Look to _home_.

 

Once, he had turned to the night sky for comfort. Once, he had turned to the stars for peace. Once, he had turned to them for hope.

 

Once, the stars on his skin had brought him joy.

 

But that was a very long time ago.

 

So long ago that it felt almost like a lifetime, an eternity, since the stars in the sky had brought anything but death and insanity and fear. So long ago that he could hardly remember when he had looked upon the stars on his skin with anything but grief and despair.

 

He’d been Named for the night, with the universe painted across his skin, and as a child that had brought him such joy. And now, one by one, his stars had gone out until only two remained and now…

 

Now they-

 

-Libs was… his star had gone flat, had gone _dark_.

 

And now _Cor_.

 

He can’t.

 

Nyx is a coward. Because he can’t. He just- he can’t. He can’t be there. He can’t watch it happen. Can’t sit at the bedside of the man who had outlived three kings only to be dying of illness – can’t watch as the last person he loves dies. And he’s so _weak_ , so selfish, because he knows that it would comfort his friend to have him there, knows that he should be there for Cor, but he _can’t_.

 

Not when he’s just lost Libs as well.

 

Not when Cor’s mark is the last splash of colour on his skin.

 

Not when everyone else is already gone.

 

He can’t.

 

So, he runs. Just like he has always done. The moment the doctor comes to tell him, to warn him that Cor has little time left, that he should probably say his goodbyes, that he’s asking for him, he runs – Libertus’ last breaths still echoing in his ears.

 

He runs and he’ll never forgive himself for it.

 

He runs to a beach and he curls up in the sand, chin resting on his knees and his arms wrapped around himself in a bastardised hug – his left hand wrapped around his right shoulder, the darkness burning after nearly four decades of _colour –_ as he stares out at the quiet sea. Trying and failing to find some comfort. The stars glisten on the water, so bright that he can’t tell where the water ends and the sky begins but for the gentle movement of the waves.

 

It should be peaceful.

 

It’s not. It just hurts, a little, somewhere beneath the numbness.

 

The icy tide brushes against his bare feet, the cold seeping into his bones but he doesn’t care. Can hardly even feel it. Just like he can’t feel the chill in the air, despite the thin clothes he wears and the goosebumps rising on his skin.

 

He just doesn’t care. Not about any of it.

 

Instead, he breathes in sea air and listens to the sound of the waves and he lets himself pretend, just for a little while. He lets himself pretend that he is just a kid again – sitting on the shores of Galahd, everyone he loves still living, his skin covered in vibrant colour instead of faded black. He lets himself pretend that everything is _alright_ -

 

-his abdomen _burns_ , burns like someone has pressed white-hot metal to it and _twisted_ , and Nyx gasps, curling even tighter into himself, muffling his scream – a scream that is half pain and half _grief_ – in his knees.

 

And then the pain fades, leaving behind it the knowledge that another of his stars – that the _last_ of his stars – has gone out. The knowledge that Cor-

 

Cor is dead.

 

~~It is all his fault~~

 

~~Cor is dead and he hadn’t been there with him~~

 

Nyx doesn’t move. He just sits there, staring out at the sea. It doesn’t matter anymore.

 

There isn’t anything left for him back there, anyway.

 

Nothing but more corpses to bury.

 

He doesn’t move and he doesn’t cry. Not because he doesn’t care, not because he doesn’t– because he _didn’t_ love Cor, not because he doesn’t grieve.

 

He doesn’t cry because he has no tears left, nothing but the void in his chest.

 

And, in the darkness of the night, that void gapes wide.

 

 

* * *

 

He doesn’t know how long he sits there, blank-faced and barely blinking, with one hand pressed to his shoulder and the other clenched over his abdomen and the gaping hole in his chest.

 

It feels like ice.

 

Except it’s like he’s been cold for so long all he feels now is numb.

 

Numb and drained and _empty_. Like someone has reached into his chest and yanked his heart out and left him bleeding and gasping and broken.

 

Left him _shattered_ into a million little pieces.

 

~~A million lightless stars.~~

 

~~Stars burn cold just before their death and oh, but Nyx understands why now.~~

 

Nyx breathes through the shattered ice in his chest and it doesn’t hurt. Nothing does, even as his fingers dig into his skin and blood tracks across his skin. He watches it, as it falls into the waters below, and he feels nothing.

 

Not even as it’s joined by something that drips down his chin.

 

A weight appears behind him and Nyx leans back into the warmth-not warmth of the Storm, uncaring of the tears and blood still trailing down his skin as he closes his eyes and soaks in the scent of ozone and wind and fresh rain and _grandfather_.

 

He turns his face in his grandfather’s neck and _breathes_ and, with each breath, the ice both warms and shatters a little more.

 

(Because his grandfather – the one who half-raised him, who saved his life more than once - is the one being that Nyx will never lose. Not like he’s lost everyone else.

 

Not like he’s lost his stars)

 

The ground rumbles beneath him and the air chills and the waves _crash_ and when he opens his eyes again it’s to the sight of three of the Six, watching him, and the fourth a familiar presence at his back.

 

And it is Ramuh who begins, who explains the choice they have made, knowing him best, speaking in that same thunder rumble and lightning crash that he knows so well. It is Leviathan who makes the offer, who asks him, freedom in every line of her scales. It is Titan who rumbles the warnings, steadfast as the ground beneath their feet.

 

Shiva says nothing, but she stands there amongst her siblings all the same.

 

Leviathan, the Tidemother, holds out a hand and it is only right that it is the serpent of the sea – who embodies freedom in every instance of the word – who reaches out to him in this.

 

Nyx smiles. He smiles, a bastard echo of so long ago, and he reaches out.

 

He reaches out and grasps the hand.

 

The Queen of the Driftwood throne pulls him up.

 

She pulls him up. Up and _out_.

 

 

* * *

 

tHe worLd

            s

                        _s_

                                    **_s_**

_s_ t **u** T _t_ **e** _R_ s

 

 

* * *

 

he

is

uNm **A** _d_ E

 

 

* * *

 

A nameless boy lands amongst the trees with a booming crash.

 

And a scream.

 

His eyes fly towards a child, no more than eight, his skin rippling and bulging with jungle green magic, and _oh._

Oh.

 

_You cannot be who you once were_ , echoes in his mind as he stares at this child and oh. He hadn’t known. Hadn’t realised what it would mean.

 

This time- it already has a Nyx Ulric and that boy, that soul, isn’t him.

 

He isn’t Nyx Ulric. He’s an Ulric, that hasn't changed, he can feel that deep down in his soul - but he isn't _Nyx_. The name doesn’t ring true in his bones anymore.

 

He’s Nameless.

 

~~He doesn’t think it would have changed his mind, even if he had.~~

 

He moves before he thinks – before he truly processes what it is his eyes are telling him, what it is he’s just realised, what it is that he _is_ – stumbling over and around familiar clothes and boots that are suddenly too big, and that’s something to panic over later, and skids to his (too-small) knees beside the child who is writhing in the dirt.

 

Hand on his chest, he presses _down_ , both grounding and domineering – using his own magic, so tired but older and trained and far more powerful than a boy who isn’t yet ten, to wrestle this child’s magic into submission as the boy screams and his magic fights and there are kinder ways to do this, softer ways, but all of them take time.

 

Time that they don’t have.

 

Time that would leave the boy in a type of agony that he can _taste_ , that he knows down to his bones, and no. He won’t let this boy suffer as he had.

 

He won’t _burn_ with his magic; he won’t bleed and break with it, not like he had. Not if he has anything to say about it.

 

So he presses down and he forces the boys magic to obey and eventually screams peter out into gasping sobs and he pulls back, pulls away, but not fast enough as the kids magic _reaches_.

 

There’s a _click_ as something – as their magic – falls into place and he shudders as a tiny body forms, the void in his chest lessening just a little, and the kid gasps and leans towards him and he-

 

_Brother_ , his magic sings in his chest, and he flinches away from the child staring at him with teary, blurry eyes.

 

It makes sense, of course it does, because they aren't the same person. He isn't Nyx Ulric, not anymore, he’d given up that part of himself to do this even if he hadn't truly understood what it was he was giving. And, even before that, they weren't the same person - not even close, not for a very long time, and he already hopes that this boy will never become anything like he is - but he is still Regis' son.

 

He isn't Nyx Ulric, but he is an Ulric and a son of Regis Lucis Caelum, and their magic recognises that. It is no wonder than the bond between them labels them _brothers_. Kin calls to kin, after all.

 

But he has just buried the last boy his magic called brother and he _can’t_.

 

He can’t.

 

He stumbles back, and back, and back, staring at his younger- at the child who can’t look away from him and he-

 

He doesn’t-

 

What is he-

 

“ _Nyx?”_ A voice, so familiar, gasps from the edge of the clearing and it wrenches in his heart even as he spins.

 

His mother ( _not his mother_ , _he’s not Nyx, his mother is **dead**_ ) stands there – and there’s a boy behind her who he refuses to look at because he knows who it will be it and it _hurts,_ hurts so much because his arm is black and the kid at his side still has rich earth browns trailing down his shoulder and it hurts – looking horrified.

 

She’s looking at **him.**

Something in him breaks a little more.

 

* * *

 

**Notes for the Chapter:**

> I wasn't actually planning on updating this fic next but the muse goes where the muse goes. The next update will probably be my Styx fic but ¯\\_(ツ)_/¯  
> I'm also not sure this is entirely coherent or as sad as I wanted it to be but I'm tired and I'm ill so whatever, have at


End file.
